Property and Equipment (Details) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Property, Plant and Equipment [Line Items] | ||
| Property, Plant and Equipment, Gross | $ 4,479 | $ 4,308 |
| Less accumulated depreciation and amortization | (3,642) | (3,265) |
| Property and equipment, net | 837 | 1,043 |
| Furniture and office equipment [Member] | ||
| Property, Plant and Equipment [Line Items] | ||
| Property, Plant and Equipment, Gross | 388 | 388 |
| Leasehold improvements [Member] | ||
| Property, Plant and Equipment [Line Items] | ||
| Property, Plant and Equipment, Gross | 408 | 408 |
| Laboratory equipment [Member] | ||
| Property, Plant and Equipment [Line Items] | ||
| Property, Plant and Equipment, Gross | 2,548 | 2,466 |
| Computer equipment [Member] | ||
| Property, Plant and Equipment [Line Items] | ||
| Property, Plant and Equipment, Gross | $ 1,135 | $ 1,046 |